Software updates download is very slow

Sit down before you read this, folks....

I went into my AT&T modem configuration to see if there was anything I could change. There was only one thing: the MTU setting for maximum packet size. It was at 1500. I recall from before that it had to be 1492 or lower for some DSL modems to work--the PPoE modems in particular. i don't think this one is, but I changed it anyway to 1492. No modem reboot required.

The AppleTV software update via iTunes on my MacBook went from 14 hours to 15 minutes, and it's DL'ing as I write this--7 minutes left.

Simple as that. No, I can't explain it. I'm going to tell my Apple support guy.

Meanwhile, I think this explains why people on Comcast don't have the problem and some of those on Verizon and AT&T do--Verizon and AT&T are using DSL not cable, the modems are different, possibly PPoE, and in any case require a lower MTU, like 1492. There are sites on the Internet that will tell you the optimum MTU for your system.

So for the person here switching from Verizon to Comcast, if it's for this reason alone, try resetting your MTU on your modem first.

Same performance here - ~ an hour to download Safari 7.1 and about 13 hours to download IOS8 for the iPad. Changed MTU to 1492 - same thing. I've been using Google DNS for several years - that's not it either. Maybe the servers are really just that slow?

On East coast in PA, with FIOS and I am having extremely slow download speeds trying to get iOS 8 and Yosemite 10.10 Beta.

Is it something with FIOS to Apple networks? Or is FIOS throttling these types of downloads. Anyone have any answers?

My maximum MTU happens to be 1492. You may want to check yours by this method:

In Mavericks, go to Terminal. Start pinging at any arbitrary number, say 1472, and keep lowering it by increments of 10-12 until you no longer get the "frag needed" or similar message. You can stop the pinging with a Control-C.

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ping -D -s 1472 www.dslreports.com

Press Enter. Then reduce 1472 by 10 until you no longer get the "packet needs to be fragmented" error message. Then increase by 1 until you are 1 less away from getting the "packet need to be fragmented" message again.

Add 28 more to this (since you specified ping packet size, not including IP/ICMP header of 28 bytes), and this is your MaxMTU.

Note:If you can ping through with the number at 1472, you are done! Stop right there. Add 28 and your MaxMTU is 1500.

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My maximum number turned out to be 1464, and 1464 + 28 is 1492.

Then, if that doesn't work with the Apple downloads, it may be their servers. But my result was instantaneous and dramatic.

Changing the MTU didn't work for me but I didn't expect a difference because I'm not using PPOE. I remember FiOS offered an "optimization" tool years ago, just before Windows 7 and Snow Leopard were released but they claim it's no longer necessary. In fact, Verizon instructs users to use a "removal" tool to revert their settings back to defaults if users are using OSX ML or later. Changing the MTU was a last gasp effort to try to get it working while I wait for my new ISP to come out to install service. I'm not switching solely because of this issue. I'm switching because this is only one of numerous issues I've experienced with FiOS over the past 18 months. I know there is no such thing as a perfect ISP but at least those living around me who have Comcast as their provider can download and stream on Apple devices with no problem. When Verizon's tier 1 support basically said in so many words 'oh well, tough luck', I knew it was time for a change. Thankfully, I have a choice.

For what its worth, after 4 days of trying to download iOS 8, I finally got it to work.

Verizon FIOS DNS servers were the problem for me. Went through a list of free DNS servers using this site http://pcsupport.about.com/od/tipstricks/a/free-public-dns-servers.htm and I chose first the Google servers (easiest to type in 😉 ) & it didnt change anything. Still got the dreaded "Connecting to Apple Servers" box.

Used the first DNS server on the list....Level3

209.244.0.3 & 209.244.0.4

and gave those a try.......SUCCESS!

6 MINUTES TO DOWNLOAD THE UPDATE!!!!!!

6 Minutes from this!!!

I took Techlaws suggestion and changed my DNS since I have Verizon FIOS. Instead of using googles servers I changed mine to 4.2.2.2 and the google servers that were mentioned. As soon as I made the change my download speed went from 85kb to 57MB per second.

Great suggestion! What you suggested resolved my issue on FIOS.

That is clever - it confirmed 1492 for my ideal MTU size, but that didn't seem to make any difference. Since people are getting different results by changing DNS servers, it seems like *some* of the Apple servers may be slow, and some not.

The first device I updated was my iPad - about 18 hours to download and update. For my iPhone, I decided to try the DNS server trick. I got a list with namebench and started working down it - deleted out the Google DNS (which was 3 and 7 in namebench) and started trying others. If the dreaded "connecting to apple servers" box comes up, just quit iTunes, delete that IP in DNS settings, add the new one and apply it, then try again. When I got to number 9 (an earthlink server) - bingo. Downloaded in 6 minutes.

That implies there is something wrong with Apple's CDN, or the way iTunes is using it. It's not that all the servers are overloaded, it's that the download requests are being spread out properly among the servers. This OSX Daily article says people are having good luck downloading the firmware directly:

http://osxdaily.com/2014/09/17/ios-8-ipsw-download/

which has the same implication.

I wish I'd thought to try downloading over and over with the Google DNS, to see if it would eventually hook me up with a fast server, regardless of what DNS I use. I suspect that might be the case.

Jason:

"Instead of using googles servers I changed mine to 4.2.2.2 and the google servers that were mentioned."

Could you clarify that for me? I thought the Google DNS settings were 8.8.8.8 and 8.8.4.4. The one you mention, 4.2.2.2 sort of looks like a Google DNS--is it?

KenV54 wrote:

Jason:

"Instead of using googles servers I changed mine to 4.2.2.2 and the google servers that were mentioned."

Could you clarify that for me? I thought the Google DNS settings were 8.8.8.8 and 8.8.4.4. The one you mention, 4.2.2.2 sort of looks like a Google DNS--is it?

4.2.2.2 is the IP address of a DNS server owned by the company Level 3 Communications.

Steve,

"That is clever - it confirmed 1492 for my ideal MTU size, but that didn't seem to make any difference. Since people are getting different results by changing DNS servers, it seems like *some* of the Apple servers may be slow, and some not."

Given the various reports here about DNS servers, I wonder whether my changing the MTU size was really what did it in terms of DLing the AppleTV software update via iTunes, or whether it was just coincidental with a random but good DNS connect with one of the Apple servers at the same time. I didn't have any way of going back and checking it out, since I had nothing left to update from Apple--I had already DL'ed the TV update and the Yosemite Public Beta 3 2 GB file. And I had also been trying to update the AppleTV software via the AppleTV itself, using the same router (with the router DNS set at 8.8.8.8) and modem combination, with the same excruciatingly slow download.

The bottom line for me at this point is that there is an interface problem with the Apple servers which affects different carriers differently (e.g., FIOS, Uverse, Comcast) and which may be worked around using various DNS servers and/or changing the MTU setting. Ultimately this is Apple's problem to solve, it seems to me. Apple presumably now has this information via my own case and maybe via others, but what they are going to do with the information, and when, is another matter.

I asked a friend to try downloading repeatedly without changing anything to see if it's possible to win CDN roulette - i.e. if you get the "connecting" dialog, just quit iTunes and start over. So far, no luck. I didn't think of that either until I was all out of things to update . . .

I changed my dns to the OpenDNS numbers, and bingo! My download time went from some ridiculous 33 hours to... 11 minutes!

(Note that you have to stop the slow download and begin a new one only after you have changed dns numbers to have this work.)

Thanks community!